A little late in the thread here, but my affirmative action knowledge comes mainly from higher education. If I’m recalling my law classes with any specificity, I believe the “compensation for past ills and discrimination” argument for affirmative action was pretty much eradicated in the Bakke case in the 1970s… and the Gratz and Grutter cases a few years ago ended any conversation on that level. The justification for affirmative action, in higher education at least, is the “compelling educational value” that a diverse student body presents. Even then, such programs must be narrowly tailored and used in conjunction with other efforts.
Speaking as someone who went to school on an affirmative action scholarship - and who wouldn’t have been able to afford to go to college and live on campus if not for the scholarship - there were always a few people who looked White at programs I attended. These programs, BTW, were open to any student who wanted to attend. While students of color got the invitations in the mail, if you were a White kid hanging out in the library, smelled food and wanted to get some (after the speeches, recognition of the committee, step show, etc.) you certainly could. One of my buddies was half Latino, half White, and looked like someone out of 90210. I wouldn’t say he advertised the fact that he was half Latino, but several people knew and he stayed active in the program for several years.
To answer the OP, in the case of my scholarship, I was interviewed by an admissions officer, who asked me a lot of questions about my education, my parents (including where they were from)… it was a long process. My hypothesis is that if you are phenotypically similar to the group you are claiming to be a member of, much of the questioning is blunted… just enough to fill out the forms correctly. If you don’t, I’d expect to hear questions about one’s lineage, etc., come up quite a bit. And I would think that such a person (legitimately) would be prepared for such questioning, or even bring it up. (My aforementioned friend talked about his frustration in being presumed White, and said he made a point of letting people know his heritage fairly early in relationships.) If you were to apply to a program or for a scholarship, you’d have to be fairly adamant, if not downright surly, to avoid answering questions about your parents’ ethnic background, their level of education, and so forth. Or you could lie, I suppose.
Then there’s the experience of being part of a minority program - convocations, meetings, that sort of thing. Again, if one was pretty bold and had no problem lying to people about your heritage - because in the cocktail party conversations, I’m certain someone would ask, “What’s your ethnic background?” if it wasn’t evident or assumed - you might make it through for a while, but that would probably raise the antennae of the administrators in charge of the program, and they’d investigate.
If it’s the sort of thing that is done without meeting someone face-to-face, I guess you might get away with it. But unless you were applying to such a program for the purpose of exposing the hypocrisy of affirmative action, I think that would be ethical suicide. At some point it would become known (perhaps through your resume, professional networks, etc.) that you pretended to be African American to gain some advantage in a grant or contract competition. I’d think you’d be looked at with a great deal of scorn if you chose to do something like this.
I have a friend who administers a program for students of color at a prestigious technical university - it’s a summer program to give kids a chance to take some classes, get acclimated to the campus, and make connections with their peers and profs. At one point he had federal money supporting this program so he had to ensure that all of the kids were students of color. However, every now and then a White student would apply to the program. He would send the student a personal note, explaining that the program was expressly for students of color, but invite the student to the “open” events (BBQs and receptions) if he/she was interested. Occasionally a student would respond back, making the case for why he or she thought the program would be a good fit for him or her. In this case, if the student qualified in all other aspects, he would ask the institution to sponsor the student and allow him or her to participate in the program. (It was something of a catch-22, because a lot of students looked down on the program, despite the fact that these students often ended up doing quite well, graduating with honors, and the like.) My friend would say, “If a White student is willing to do the work, and undergo the same scrutiny every student of color in the program goes through as a participant, he’s welcome to join.”
I haven’t talked to him since the SCOTUS ruled on Gratz and Grutter so I’m not sure how his approach has changed, if at all.